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Established Function (established + function)
Selected AbstractsEstimating the digestibility of Sahelian roughages from faecal crude protein concentration of cattle and small ruminantsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 9-10 2006E. Schlecht Summary Studies on diet selection and feed intake of ruminants in extensive grazing systems often require the use of simple approaches to determine the organic matter digestibility (OMD) of the ingested feed. Therefore, we evaluated the validity of the one-factorial exponential regression established by Lukas et al. [Journal of Animal Science 83 (2005) 1332], which estimates OMD from the faecal crude protein (FCP) concentration. The equation was applied to two sets of data obtained with free grazing and pen-fed cattle, sheep and goats ingesting low and high amounts of green and dry vegetation of Sahelian pastures as well as millet leaves and cowpea hay. Data analysis showed that the livestock species did not influence the precision of estimation of OMD from FCP. For the linear regression between measured and estimated OMD (%) across n = 431 individual observations, a regression coefficient of r2 = 0.65 and a residual standard deviation (RSD) of 5.87 were obtained. The precision of estimation was influenced by the data set (p = 0.033), the type of feed (p < 0.001) and the feeding level (p = 0.009), and interactions occurred between type of feed and feeding level (p = 0.021). Adjusting the intercept and the slope of the established exponential function to the present data resulted in a compression of the curve; while r2 remained unchanged, the RSD of the regression between measured and estimated OMD was reduced, when compared with the results obtained from the equation of Lukas et al. (2005). Estimating OMD from treatment means of FCP greatly improved the correlation between measured and estimated OMD for both the established function and the newly fit equation. However, if anti-nutritional dietary factors increase the concentration of faecal nitrogen from feed or endogenous origin, the approach might considerably overestimate diet digestibility. [source] The beneficial role of intermediate clarification in a novel MBR based process for biological nitrogen and phosphorus removalJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2009MinGu Kim Abstract BACKGROUND: A novel membrane bioreactor (MBR) is described, employing an intermediate clarifier. Unlike the established function of a final clarifier in a conventional biological nutrient removal system, the role of an intermediate clarifier has rarely been studied. Thus, this work focused on explaining the fate of nutrients in the intermediate clarifier, as influenced by the hydraulic retention time (HRT) of the preceding anaerobic bioreactor. RESULTS: The system was tested with two different anaerobic/anoxic/aerobic biomass fractions of 0.25/0.25/0.5 (run 1) and 0.15/0.35/0.45 (run 2) using synthetic wastewater. The major findings of the study were that phosphorus (P) removal was affected by the role of the intermediate clarifier. In run 1, P was removed at a rate 0.16 g d,1 in the intermediate clarifier while in run 2, additional P was released at 0.49 g d,1. The nitrogen (N) removal efficiencies were 74 and 75% for runs 1 and 2 respectively, while P removal was 91 and 96%. P uptake by denitrifying phosphate accumulating organisms (DPAOs) accounted for 41,52% of the total uptake in the MBR. CONCLUSIONS: This study found that the intermediate clarifier assisted chemical oxygen demand (COD), N, and P removal. With respect to the fate of P, the intermediate clarifier functioned as an extended anaerobic zone when the HRT of the preceding anaerobic zone was insufficient for P release, and as a pre-anoxic zone when the anaerobic HRT was adequate for P release. Copyright © 2008 Society of Chemical Industry [source] Analysis of isotope ratios in vitamin K1 (phylloquinone) from human plasma by gas chromatography/mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2006Kerry S. Jones Vitamin K1 is a fat-soluble vitamin required for the , -carboxylation of vitamin K-dependent proteins. Recent work has suggested an important role for vitamin K1 in bone health beyond its more established function in the control and regulation of blood coagulation. However, current UK recommended intakes do not reflect this recent evidence. The use of stable isotopes provides a powerful tool to investigate vitamin K kinetics, turnover and absorption in man, although published methods have reported difficulties in the extraction and analysis of isotope ratios of vitamin K in human plasma. In this paper, we report a new methodology for the extraction and measurement of isotope ratios in vitamin K1. Sample clean-up is achieved with liquid-liquid extraction, enzyme hydrolysis with lipase and cholesterol esterase, and solid-phase extraction. Isotopic analysis of the pentafluoropropionyl derivative of vitamin K1 is performed by gas chromatography/mass spectrometry (GC/MS). The limit of quantitation is equivalent to at least 0.3,nmol/L and the method is demonstrated to be linear over a range of enrichments. This method provides a robust alternative to previous work requiring the use of semi-preparative high-performance liquid chromatography (HPLC). Copyright © 2006 John Wiley & Sons, Ltd. [source] Beta-catenin accumulation in the progression of human hepatocarcinogenesis correlates with loss of E-cadherin and accumulation of p53, but not with expression of conventional WNT-1 target genesTHE JOURNAL OF PATHOLOGY, Issue 2 2003Wilhelm Prange Abstract Beta-catenin integrates intracellular WNT signalling and the intercellular E-cadherin,catenin adhesion system. To date, little is known about the role of ,-catenin activation and nuclear accumulation in hepatocarcinogenesis. This study has analysed ,-catenin expression patterns in human dysplastic nodules (DNs), as well as in hepatocellular carcinomas (HCCs) in comparison with proliferation, expression of WNT-1 target genes, E-cadherin, and p53. One hundred and seventy HCCs and 25 DNs were categorized according to established criteria and analysed for the expression pattern of ,-catenin. Analysis of the proliferative activity and expression of E-cadherin, cyclin D1, MMP-7, c-myc, and p53 was performed on a representative subgroup of cases. All DNs lacked nuclear ,-catenin, while 36% of all HCCs were positive, with the number of nuclear stained cells ranging from less than 1% to more than 90%. Increasing nuclear accumulation of ,-catenin correlated with reduced membranous E-cadherin expression and nuclear p53 but not with proliferation. Cyclin D1, MMP-7, and c-myc expression was detected in 54%, 26%, and 65% of HCCs, respectively, but did not correlate with nuclear ,-catenin, proliferation, or grading. Sequence analysis of the ,-catenin gene revealed no detectable mutations in DNs, but mutations in the GSK-3, binding site were present in 14.3% of the HCCs. In conclusion, this study has demonstrated that nuclear accumulation of ,-catenin is a frequent progression event in human hepatocarcinogenesis which correlates with nuclear p53 accumulation and loss of membranous E-cadherin, but not with the expression pattern of established WNT-1 target genes. It is hypothesized that the role of ,-catenin in human HCC differs significantly from its established function in colon carcinogenesis. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||